The use of mixed matrix membranes (MMMs) comprising metal–organic frameworks (MOFs) for the separation of COsub.2 from flue gas has gained recognition as an effective strategy for enhancing gas ...separation efficiency. When incorporating porous materials like MOFs into a polymeric matrix to create MMMs, the combined characteristics of each constituent typically manifest. Nevertheless, the inadequate dispersion of an inorganic MOF filler within an organic polymer matrix can compromise the compatibility between the filler and matrix. In this context, the aspiration is to develop an MMM that not only exhibits optimal interfacial compatibility between the polymer and filler but also delivers superior gas separation performance, specifically in the efficient extraction of COsub.2 from flue gas. In this study, we introduce a modification technique involving the grafting of poly(ethylene glycol) diglycidyl ether (PEGDE) onto a UiO-66-NHsub.2 MOF filler (referred to as PEG-MOF), aimed at enhancing its compatibility with the 6FDA-durene matrix. Moreover, the inherent COsub.2-philic nature of PEGDE is anticipated to enhance the selectivity of COsub.2 over Nsub.2 and CHsub.4. The resultant MMM, incorporating 10 wt% of PEG-MOF loading, exhibits a COsub.2 permeability of 1671.00 Barrer and a COsub.2/CHsub.4 selectivity of 22.40. Notably, these values surpass the upper bound reported by Robeson in 2008.
At present, China is transforming into a green development mode in all respects, and improving green energy efficiency is a key component of this transformation. Using panel data of 2011–2018, this ...research adopts the Super-SBM (Slack-Based Model) to calculate the green energy efficiencies of China's 29 provinces and a GML (Global Malmquist-Luenberger) index method to explain the efficiency changes. Empirical analysis draws the following conclusions: 1) China's green energy efficiency presented a slowly decreasing rather than increasing trend. 2) Technological progress was a major factor in efficiency improvement. However, its contribution was canceled by energy overuse. 3) Provinces with low green energy efficiency tend to geographically gather in the regions with rich energy resource endowment. Instead, provinces with high green energy efficiency are relatively geographically scattered, and most of them are China's most developed regions. 4) Green energy efficiencies among China's four major regions have significant differences. Generally, the mean level is east > northeast > west > central. 5) The key policy directions to improve China's green energy efficiency include using transfer payment to balance the regional development, breaking down the barriers among provinces to facilitate energy circulation, and refining energy price structure to mitigate rebound effects.
•Green energy efficiency of each province in China is measured by the Super-SBM.•A GML index method is used to decompose the efficiency changes.•China's green energy efficiency presented a slowly decreasing trend in 2011–2018.•Energy overuse hindered the improvement of China's green energy efficiency.•Transfer payment, breaking down provincial barriers, and refining energy price structure are suggested.
Motivated by the fact that both security and energy efficiency are the fundamental requirements and design targets of future satellite communications, this letter investigates secure energy efficient ...beamforming in multibeam satellite systems, where the satellite user in each beam is surrounded by an eavesdropper attempting to intercept the confidential information. To simultaneously improve the transmission security and reduce power consumption, our design objective is to maximize the system secrecy energy efficiency (SEE) under the constraint of total transmit power budget. Different from the existing schemes with high complexity, we propose an alternating optimization scheme to address the SEE problem by decomposing the original nonconvex problem into subproblems. Specifically, we first utilize the signal-to-leakage-plus-noise ratio metric to obtain closed-form normalized beamforming weight vectors, while the successive convex approximation method is used to efficiently solve the power allocation subproblem. Then, an iterative algorithm is proposed to obtain the suboptimal solutions. Finally, simulations are provided to verify the superiority of the proposed scheme compared to the benchmark schemes.
It is significant to evaluate accurately energy efficiency of ethylene cracking furnace as the highest energy consumption device in ethylene production. However, previous energy efficiency evaluation ...methods mainly concentrate on system-level evaluation of ethylene production and fail to consider effects of production load on operation conditions, which are unsuitable for detailed evaluation online. Considering single energy efficiency content and impractical improvement scheme of DEA and unreasonable static baselines in TOPSIS, a modified TOPSIS energy efficiency evaluation method is proposed. A set of new energy efficiency indicators is designed through matter conversion and energy transformation together with matter and energy interaction. To acquire real-time energy efficiency a simulation model of cracking furnace is established by employing radial basis function neural network. To improve evaluation accuracy, the relations among energy efficiency and operation conditions and production load are quantified by calculation formulas of energy efficiency indicators and functions extracted from simulation model. The sequential quadratic programming algorithm is suggested to solve dynamic baselines according to real-time production load by adjusting operation conditions within constraints. Furthermore, optimal operation conditions are provided by searching for maximum comprehensive energy efficiency. Finally, validity of proposed evaluation method is illustrated by applying in a practical cracking furnace.
•A revised TOPSIS energy efficiency evaluation method for cracking furnace is proposed.•Dynamic baselines are determined according to real-time production load.•A set of new energy efficiency indicators is designed and predicted in real time.•The relations of energy efficiency and operation conditions and load are quantified.
Mika H. Sipponen
Angewandte Chemie (International ed.),
September 13, 2021, Letnik:
60, Številka:
38
Journal Article
Recenzirano
Odprti dostop
“The most important future applications of my research are energy efficiency and environmentally friendly materials … Young professors are not prepared for the amount of emailing and housekeeping ...tasks that are out there for you …“ Find out more about Mika Sipponen in his Introducing … Profile.
Many countries have implemented policies to encourage higher Energy Efficiency (EE) implementation, but they seem insufficient and significant EE opportunities are unrealized. It is thus important to ...understand which internal strategic drivers can help further improve EE implementation by a firm. We develop a theoretical framework and empirically investigating how corporate strategy influences firms' EE implementation on top of EE policies. Drawing from the literature on Natural-resource-based view and Proactive Environmental Strategy, we hypothesize the impacts of several strategic capabilities, including shared vision, top management support and stakeholder integration on a firm's EE implementation. We test our hypotheses using combined secondary data of 572 publicly traded firms from the CDP report, COMPUSTAT Fundamentals North America and Global, and the World Economic Forum. Our study enriches the literature on firms' perceived EE drivers by dissecting the nuanced impacts of different strategic capabilities and exploring new dimensions. Our findings also suggest important policy insights in encouraging higher industrial EE implementation. It remains important to strengthen EE policies and regulation. However, to make further leaps in EE implementation, policy efforts could be spent in information campaigns helping redirect interpretation of EE improvements toward opportunities and away from risks/threats.
•Policies are important, but insufficient to drive energy efficiency implementation.•Firms' internal strategic capabilities are crucial for a leap in energy efficiency.•The management of climate change should be perceived as opportunities, not risks.
Multi energy demand response is an important measure to achieve the economic and efficient operation of the integrated energy system (IES), which is of great significance to promote the sustainable ...development of the IES. The concept of demand response (DR) is extended to IES, and a double objective operation optimization model of IES considering integrated demand response (IDR) mechanism is proposed. Firstly, based on the electro-thermal IES, this paper proposes a demand response mechanism considering electric load and thermal load. According to the load composition (transferable load, reducible load, adjustable thermal load), the load management strategy is established. Then, based on the DR mechanism of electro-thermal IES, a multi-objective operation optimization model is established for the first time, which takes the economic benefits and comprehensive energy efficiency as the objective function. The model involves the equipment constraint in the process of energy production and energy transmission. The relationship between total operation cost and comprehensive energy efficiency of electro-thermal IES is analyzed in the part of Data, Simulation Results and Analysis. Finally, the results show that the model effectively improves the economic benefits and comprehensive energy efficiency of IES, and reduces the pollutants emissions to a certain extent.
•The information and energy flow framework of an integrated energy system is proposed.•An integrated demand response mechanism considering load composition is established.•A dual objective operation optimization model of integrated energy system is established.•The model aims at economy and comprehensive energy efficiency.•The model can improve the economic, efficiency and environmental benefits of the system.
The conversion and utilization of carbon dioxide (COsub.2) have dual significance for reducing carbon emissions and solving energy demand. Catalytic reduction of COsub.2 is a promising way to convert ...and utilize COsub.2. However, high-performance catalysts with excellent catalytic activity, selectivity and stability are currently lacking. High-throughput methods offer an effective way to screen high-performance COsub.2 reduction catalysts. Here, recent advances in high-throughput screening of electrocatalysts for COsub.2 reduction are reviewed. First, the mechanism of COsub.2 reduction reaction by electrocatalysis and potential catalyst candidates are introduced. Second, high-throughput computational methods developed to accelerate catalyst screening are presented, such as density functional theory and machine learning. Then, high-throughput experimental methods are outlined, including experimental design, high-throughput synthesis, in situ characterization and high-throughput testing. Finally, future directions of high-throughput screening of COsub.2 reduction electrocatalysts are outlooked. This review will be a valuable reference for future research on high-throughput screening of COsub.2 electrocatalysts.
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